Ammeter wiring

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Jul 8, 2008 | 08:11 PM

tomkat5

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Ammeter wiring

I've got a quick question re: proper wiring of the ammeter on a 1970 F250 that has the guage, not the idiot light. I have the diagrams for wiring the alternator..no problem. But can one of you subject matter experts clue me in as to how the ammeter wiring is supposed to connect in? I have the red and yellow wires to / from the ammeter isolated in the cab, but what goes where in the engine compartment? Is there supposed to be a shunt?

Thanks in advance for any help...

Jul 9, 2008 | 11:38 AM

swcash

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From: Anaheim, California

Don't expect much from your "charge indicator" as Ford refers to the gauge.
There is a shunt, but don't look under the dash for it, the shunt is accomplished by connecting the two "charge indicator/ammeter" wires to the same black wire between the alternator and the start relay.
The red wire can connect to the battery side of the start relay, and the yellow wire connects to the same black wire from the alternator, but the connection is very near the alternator.

You may get more gauge action by connecting the yellow wire to the heavy black wire AT the alternator.

I have owned three of these trucks with the "charge indicator/ammeter" and in every case the needle just barely deflects regardless of the load on the alternator.
Do yourself a favor and install a nice voltmeter. You will get a whole lot more information from the voltmeter than from the "Charge Indicator/Ammeter"
Squido

Jul 9, 2008 | 05:49 PM

baitmaster

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From: nevada

I have a 1 wire 100 amp alt on my '72. If I put a voltmeter in it, is it just the wire from the alt hot post to the gauge to the battery?

Jul 10, 2008 | 01:38 AM

swcash

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From: Anaheim, California

My personal preferences:
I would attach the one wire from the alternator to the battery side of the start relay.
I would connect the + side of the voltmeter also to the battery side of the start relay.
The _ side of the voltmeter needs to be connected to a good ground, the first choice would be the _ battery. 2nd choice would be the engine block.

Make sure ALL of your battery connections are clean and tight.
Squido

Jul 10, 2008 | 08:04 PM

tomkat5

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thanks for all the tips, fellas! I'm going to try and wrap this one up over the weekend and I'll let you know how it turns out.

Cheers

Jul 11, 2008 | 01:18 PM

Red69

Tuned

Joined: Dec 2004

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From: Rock Hill, SC

An aftermarket ameter must go between the bat term on the solenoid and the battery term on the ignition switch if memory is correct. That way it will show both charge and disharge conditions. Do not ground an ameter lead ever.

Jul 11, 2008 | 11:51 PM

orich

Lead Driver

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From: **** hole San Jose ca.

Ford screwed up putting a Amp meter on after they stopped using generators. They sholud have put in a volt meter instead, to give you a better understanding of the out put of the Alternator.. my 2cents